Everyone agrees the probability of hitting a target when shooting 15bps is better than 12bps, right? Is there ANY reason to doubt that assumption?

Now is it enough to care? Hard to tell. It's too much work for anyone to take seriously. Just look at the Punkworks test. Instead of sinking tons of time and money into putting some thought into the testing... they simply formed a conclusion based on shooting a few thousand rounds of sub-par paint at people trying to run through lanes.

As lazy as that was, it's still more informative than theories you'll find in forums.